High Concentrations Of Cadmium Research Articles

Assessment of heavy metals and its treatment through phytoremediation in groundwater along River Kabul in district Charsadda

Life cannot exist without water. Water scarcity is caused by massive groundwater decline. Water contamination is the most common problem spreading worldwide quicker than ever, along with anthropogenic water scarcity. Since tainted water can harm health, water contamination is also contributing to water scarcity. Heavy metals in drinking water have plagued most Asian, African, and European nations for decades. Studies reveal that heavy metals have caused damage in Pakistan, India, and China. This study detects heavy metals in groundwater and treats them with phytoremediation along the river Kabul in district Charsadda. It also measures pH, EC, TDS, turbidity, fluoride, phosphates, nitrites, and nitrates. All indicators meet the WHO and national environmental quality criteria for drinking water, except for turbidity, which exceeds the limit of ≤5 NTU in four examined regions, reaching a maximum of 9.99 NTU. Chemical parameters were within the standard limits, except for high concentrations of arsenic (As) and cadmium (Cd) in samples from S2 (15.20 μg/L) and S1 (20.50 μg/L) compared to WHO’s 10 and 5 μg/L standards. However, the limit is within EPA Pakistan’s 50 and 100 μg/L standards for drinking water, which Pakistan still follows. Heavy metals can harm health, even at low levels. Since the majority of the study area’s population relies on groundwater for drinking and other needs, heavy metal pollution of the groundwater can cause many ailments. Thus, phytoremediation is increasingly vital to reduce these heavy metals to WHO limits to protect human health and the environment.

Possible enrichment process of Cd in the Se-rich soil area of Lanshan District, Shandong Province, China.

High cadmium (Cd) concentrations widely occured in selenium (Se)-rich soils, which has been an important obstacle in the usage of Se-rich soils. There is still no special information detailing the enrichment process and mechanism of Cd in Se-rich soils. 4474 soils and 21 rocks in Lanshan District were sampled to detect its enrichment process. The surface soils have Cd concentrations of 0.01-9.41mg·kg-1 (an average of 0.16mg·kg-1). The soil Cd concentrations were significantly correlated with soil Se concentrations. The relatively higher-Cd surface soils are distributed in Lower-middle Ordovician carbonate areas with Se-rich soils and Quaternary areas with typical anthropic activities. Surface soils in Ordovician carbonate area have the highest Cd concentrations. Soil Cd concentrations are significantly correlated with sulfophil elements (Zinc (Zn), Copper (Cu), Molybdenum (Mo), Lead (Pb) and Arsenic (As) etc.), Ca (Calcium) concentrations and soil organic carbon (SOC). The soil and rock samples from different geological units also confirmed soil Cd concentrations developing from Ordovician carbonates were higher than those from other rocks. The results indicate the soil Cd concentrations were the complex consequences of bedrock, soil-forming processes and anthropogenic activities. Higher Ca concentrations and more reduction environments result in high-Cd bedrock. CaCO3 leaching and alkaline pH, which are the special soil-forming process of carbonates, enrich Cd in soils. Agricultural and industrial activities also affect soil Cd concentrations. An enrichment model of Cd in Se-rich soils is forwarded.

The impact of lead, cadmium, and mercury on the reproduction of mountain hares (Lepus timidus L., 1758) in the north of Krasnoyarsk Krai

Reproduction is key to the survival and development of a species. Anthropogenic activities release significant amounts of toxic pollutants into the environment. In this study, we aimed to determine effects of heavy metals on some reproductive parameters of the mountain hare. Female mountain hares (n = 41) were hunted in the reference and industrially polluted areas of Krasnoyarsk Krai during four seasons. Their skeletal muscles, liver, and kidneys were subjected to atomic absorption spectrometry to determine concentrations of lead, cadmium, and mercury. The contents of lead, cadmium, and mercury were significantly higher in the hares from the contaminated areas compared to the reference sites. According to the results, the exposure to lead, cadmium, and mercury had an impact on the reproductive potential of the female mountain hares. In particular, we established correlations between numbers of embryos and corpora lutea and contents of lead in the kidneys and liver, as well as cadmium in the kidneys. The number of corpora lutea and embryonic losses in the female hares from the contaminated areas were higher than those in the hared from reference areas. However, the numbers of embryos did not differ significantly between the compared areas. Our study showed that about 40% of the liver samples and 100% of the muscle tissue samples obtained from the hares in the impact zone contained high concentrations of lead and cadmium. Therefore, hunting in these industrially polluted areas may pose a toxic hazard to the indigenous peoples living there. Further research is needed to assess potential and actual fertility, offspring survival, and other important parameters of mountain hare populations exposed to different levels of chemical pollution.

Physiological and transcriptomic analyses reveal the cadmium tolerance mechanism of Miscanthus lutarioriparia.

Miscanthus lutarioriparia is a promising energy crop that is used for abandoned mine soil phytoremediation because of its high biomass yield and strong tolerance to heavy metals. However, the biological mechanism of heavy metal resistance is limited, especially for applications in the soil restoration of mining areas. Here, through the investigation of soil cadmium(Cd) in different mining areas and soil potted under Cd stress, the adsorption capacity of Miscanthus lutarioriparia was analyzed. The physiological and transcriptional effects of Cd stress on M. lutarioriparia leaves and roots under hydroponic conditions were analyzed. The results showed that M. lutarioriparia could reduce the Cd content in mining soil by 29.82%. Moreover, different Cd varieties have different Cd adsorption capacities in soils with higher Cd concentration. The highest cadmium concentrations in the aboveground and belowground parts of the plants were 185.65 mg/kg and 186.8 mg/kg, respectively. The total chlorophyll content, superoxide dismutase and catalase activities all showed a trend of increasing first and then decreasing. In total, 24,372 differentially expressed genes were obtained, including 7735 unique to leaves, 7725 unique to roots, and 8912 unique to leaves and roots, which showed differences in gene expression between leaves and roots. These genes were predominantly involved in plant hormone signal transduction, glutathione metabolism, flavonoid biosynthesis, ABC transporters, photosynthesis and the metal ion transport pathway. In addition, the number of upregulated genes was greater than the number of downregulated genes at different stress intervals, which indicated that M. lutarioriparia adapted to Cd stress mainly through positive regulation. These results lay a solid foundation for breeding excellent Cd resistant M. lutarioriparia and other plants. The results also have an important theoretical significance for further understanding the detoxification mechanism of Cd stress and the remediation of heavy metal pollution in mining soil.

An updated ecotoxicological evaluation and health risk assessment of metal contaminants in Perna viridis mussel harvested on March to August 2018 from Pasir Gudang Coastal Area, Malaysia

Perna viridis (P. viridis) is a significant protein source globally but is often contaminated by metals due to its filter-feeding behavior. Given that Kampung Pasir Puteh, Pasir Gudang (Johor) is Malaysia's primary P. viridis harvesting site and the last health risk assessment (2015) was incomplete, the metal contamination status remains uncertain. Graphite furnace-atomic absorption spectroscopy was employed to analyze metal contaminant concentrations in P. viridis samples collected from March to August 2018, as per Malaysian legal requirements. The R2 values varied between 0.9976 and 0.9980 for P. viridis mussels and between 0.9976 and 0.9999 for seawater. The recovery for P. viridis mussels and seawater ranged from 93.95% to 106.80% and 92.73–108.84%, respectively. Precision and accuracy for both intra and inter-day measurements ranged from 0.15% to 5.49% for P. viridis and 0.05–5.58% for seawater. The concentrations of metal contaminants in P. viridis varied significantly among the different months of sampling (p < 0.05). All P. viridis samples had higher concentration of arsenic (3.16–75.80 μg g−1) than that prescribed by the Malaysian law. Higher cadmium concentration was observed during July (2.12 μg g−1) and August (2.05 μg g−1) alone. With target hazard quotients and hazard indices > 1.0, the likelihood of negative health impacts from consuming these mussels cannot be ignored. TCR values for As and Cd exceeded USEPA standards, indicating a potential lifetime carcinogenic risk from continuous P. viridis consumption. Pb (21.20–49.28 µg L−1) in all surface seawater samples was invariably higher than the allowable limit for Class 2 water areas. Metal contaminant concentrations varied significantly between P. viridis and surface seawater (p < 0.05), implying inconsistent bioaccumulation due to pollution differences. Given the significance of P. viridis mussels, concerted scientific efforts are essential to devise effective metal contaminant removal methods.

Geoenvironmental Assessment of the Impacts of Ewu-Elepe Dumpsite on Soil and Groundwater Resources at Ikorodu, Lagos State, Nigeria

The environmental status of the municipal solid waste dumpsite at Ewu-Elepe, Ikorodu Local Government Area of Lagos State was investigated. A total of seventeen (17) samples consisting of twelve (12) soils, three (3) groundwater and two (2) leachate samples were collected and analyzed for different parameters using Atomic Absorption Spectrophotometer (AAS). The results revealed that in the leachate samples, all the heavy metals, Cl- , COD, salinity, and conductivity contents showed significant increase. The physicochemical results for the groundwater samples agreed with the international standards for drinking water, except for high cadmium content (0.009mg/l) recorded in the groundwater sample W1 which exceeded the NSDWQ and WHO permissible limits of 0.003 and 0.005mg/l respectively for drinking water, and high manganese content (0.09mg/l) recorded also in W1. The results of soil samples from the dumpsite showed that the concentration of all the heavy metals, Zn (23.5mg/kg), Cu (10.8mg/kg), Cr (14.2mg/kg), Ni (3.47mg/kg) and Pb (19.0mg/kg) fall below the Sediment Quality Criteria ISQG-Low level and the Lowest Effect Range of the New York Sediment Criteria except for Cd (16.60mg/kg) which is even higher than the High Effect Range of both the New York sediment Criteria and the Sediment Quality Criteria that the soil within the dumpsite have been moderately impacted is further demonstrated by the application of environmentric parameters treatment such as Contamination Factor (CF), Geo-accumulation Index, Enrichment Factor (EF) and Ecological Risk Factor Analyses. The results of the sediment quality assessment are good evidence to confirm that the soil of the dumpsite is highly polluted with cadmium (Cd), and moderately contaminated with lead (Pb). This study reveals that the solid waste dumpsite is affecting the natural quality of the ambient environment. Therefore, indiscriminate dumping of solid waste at the dumpsite should be prohibited.

Nitrogen Fertilizer Enhanced the Vitality of Oregano (Origanum vulgare) Plants and Boosted Their Ability to Accumulate Soil Cadmium: Agro-environmental Implications

AbstractSoils with high cadmium (Cd) content can be decontaminated with phytoremediation. In this work, we aimed at adding nitrogen (N) fertilizer for enhancing the vitality of our test plant, oregano (Origanum vulgare). In a pristine soil, we added Cd at 0, 20, and 40 mg kg−1 soil (thereafter Cd0, Cd20, and Cd40) and two N rates at 0 and 340 kg N ha−1 (thereafter N0 and N1) in a 75-day pot experiment. We found that oregano dry weight increased significantly from 4.95 at control to 7.34 g pot−1 at Cd40N1 (a 148% increase). This indicated that the benefit of added N surpassed the negative effects of the Cd-borne stress. All other treatments had non-significant differences compared to the control. Cadmium content in oregano aerial biomass was zero in the unamended treatments, raised to 0.35 mg kg−1 at Cd40N0, and to 1.11 mg kg−1 at Cd40N1. Further, we assessed the plant’s performance in regard to its potential use as a phytoremediation species. We calculated the Cd soil-to-plant transfer coefficient (TC; maximum was 0.042) and the root-to-shoot translocation factor (TF; maximum 0.171). Both indices exhibited the failure of oregano as a potential hyperaccumulator. However, our findings rather confirmed our scientific hypotheses that N addition to soil boosted plant’s ability to accumulate Cd (as indicated in the significant twofold increase in shoot content of Cd and the 7.8-fold increase in TF at Cd40N1 compared to Cd40N0). We conclude that boosted vigor by added N is a promising method for enhancing phytoremediation of Cd-contaminated soils, but further field tests are necessary regarding oregano to verify those findings.

The effects of cadmium on selected oxidative stress parameters and the content of photosynthetic pigments in cucumber Cucumis sativus L.

BackgroundEnvironmental pollution by cadmium (Cd) is currently a common problem in many countries, especially in highly industrialised areas. Cd present in the soil can be absorbed by plants through the root system. AimThe aim of the present study was to investigate the effects of cadmium on the metabolic activity of cucumber plants (Cucumis sativus L.) and the accumulation and distribution of Cd in the organs of the plants. MethodsCucumber seeds (3 g) were exposed to 0.76, 1.58 or 4.17 mg Cd/L (applied as CdCl2 solutions). The activity of selected antioxidant enzymes - glutathione peroxidase (GSH-Px), superoxide dismutase (SOD) and catalase (CAT), lipid peroxidation and the content of photosynthetic pigments were determined in 6-week-old cucumber plants. In addition, intake of Cd has been determined by flame atomic absorption spectrometry (F-AAS). ResultsThe results show that the applied cadmium concentrations affected the activity of antioxidant enzymes. An increase in CAT activity and a decrease in SOD activity were observed in all cucumber organs analysed. GSH-Px activity increased in the roots and stems. Surprisingly, GSH-Px activity decreased in the leaves. The level of lipid peroxidation was usually unchanged (the only one statistically significant change was a decrease in the concentration of malondialdehyde in the leaves which was observed after exposure to the highest Cd concentration). The applied Cd concentrations had no effect on the content of photosynthetic pigments. The highest cadmium content was found in the roots of cucumber plants. Cd tends to accumulate in the roots and a small amount was translocated to the stems and leaves, which was confirmed with the translocation factor (TF). ConclusionsThe results indicate that the range of cadmium concentrations used, corresponding to the level of environmental pollution recorded in Europe, effectively activates the antioxidant enzyme system, without intensifying lipid peroxidation or reducing the content of photosynthetic pigments.

Removal of Cadmium from Public Smoking area Soil using indoor Plants and Electrical Grounding

Objectives : In this study, the absorption of heavy metals in the soil from smoking areas using indoor plants and electrical grounding was investigated to increase the utility of indoor plants for soil decontamination.Methods : Soil from plant pots in a smoking area was collected for the experimental plant pot preparations. Some of the prepared pots were connected to electrical ground via an electrode. Kidney beans (&lt;i&gt;Phaseolus vulgaris&lt;/i&gt;) were seeded, and their growth were observed. After 30 days of the cultivation, TOC (Total Organic Carbon), and metagenomics profiles in the soil was analyzed. To estimate the behavior of the heavy metals in soil and plants, Cadmium concentrations in the samples were analyzed using ICP-MS (Inductively Coupled Plasma-Mass Spectrometry).Results and Discussion : The connection of the electrical ground to the plant pot induced the rapid growth of plant (48.2 ± 2.3% increase in stem growth), compare to the plant in the pot without the electrical ground. TOC analysis showed that the soil from the grounded pots showed the highest value, compared to the control soil (3.08 ± 1.22%), and the soil from the pot without ground connection (2.3 ± 0.1%). The ICP-MS analysis indicated that the plant body in the grounded pot had the highest cadmium concentration at 0.33 ± 0.018 μg/kg. Using the metagenomic analysis, biomineralization related bacterial species (&lt;i&gt;Nocardioides&lt;/i&gt; sp., &lt;i&gt;Streptomyces&lt;/i&gt; sp., &lt;i&gt;Sphingomonas&lt;/i&gt; sp. etc.) were identified from the grounded soil sample. These results suggested that the indoor plant cultivation with the electrical ground connection as an electrical fertilizer enhances the cadmium absorption by plant, exudate secretion from the plant root, and bacterial flora change in the rhizosphere.Conclusion Cadmium in the soil from the smoking area was absorbed by indoor plant with the electrical ground. Therefore, the application of the electrical ground connection (earth) to the electrically insulated outdoor plant pots might enhance the plant growth rate and physiological activity. This application could be a novel soil decontamination method using plants.

Assessment of Metal Concentration and Bioaccumulation Factor in Surface Water and Fishes Sampled From Four Creeks in the Bonny River Estuary, Niger Delta Region of Nigeria

The indiscriminate disposal of industrial and urban waste has added to the concerns of global water pollution. Anthropogenic activities and activities of oil companies (oil spills) have also contributed to the pollution of the aquatic ecosystem in the Niger Delta region of Nigeria. This study was therefore designed to evaluate the concentration of Iron, Nickel, Lead, Cadmium and Chromium in our surface waters and our marine life. Samples of surface water were collected into 50 cl sterile plastic bottles and labelled accordingly. Twenty medium-sized tilapia fishes from about a one-kilometre radius of each site were caught and also labelled accordingly. Water and fishes from each site were then kept in a cooler, iced and immediately transported to the laboratories for analysis for heavy metals after these fishes were homogenised using a blender. Atomic absorption spectrophotometer was used for the metal analysis. Standards were prepared using tracecert of each of the above-mentioned metals. The results of these study sites (Akpajo, Okujagu, Woji and Elelenwo) had high concentrations of metals. Fishes from all these sites also had high concentration of these metals. The trend of metal concentration in the surface water as follows: Okujagu–Pb&gt;Cr&gt; Cd&gt;Fe = Ni, Akpajo–Cd&gt;Fe&gt;Pb&gt;Cr&gt;Ni, Elelenwo–Pb&gt;Cr&gt;Fe&gt;Cd&gt;Ni, Woji–Cr&gt;Cd&gt;Pb&gt;Fe&gt;Ni. Results obtained also revealed the trend of metal concentration in fish muscles as follows: Okujagu–Pb&gt;Cr&gt; Cd&gt;Fe = Ni, Akpajo– Cd&gt;Fe&gt;Pb&gt;Cr&gt;Ni, Elelenwo–Pb&gt;Cr&gt;Fe&gt;Cd&gt;Ni and Woji–Cr&gt;Cd&gt;Pb&gt;Fe&gt;Ni. Fishes and surface water sampled from these four creeks in the Bonny estuary in the Niger Delta region of Nigeria had high concentrations of iron, nickel, cadmium, chromium and lead in relation to their concentration in surface water. The results of this study revealed that metal concentration in surface water had some relative effect on their concentration in the fishes. This, therefore, means consumption of these fishes may lead to the accumulation of these metals in man to a toxic concentration. This may be one of the reasons for the increase in some heavy metal-related health issues (diabetes, renal diseases) in this region.

Stable Isotope Analyses Reveal Impact of Fe and Zn on Cd Uptake and Translocation by Theobroma cacao.

High concentrations of toxic cadmium (Cd) in soils are problematic as the element accumulates in food crops such as rice and cacao. A mitigation strategy to minimise Cd accumulation is to enhance the competitive uptake of plant-essential metals. Theobroma cacao seedlings were grown hydroponically with added Cd. Eight different treatments were used, which included/excluded hydroponic or foliar zinc (Zn) and/or iron (Fe) for the final growth period. Analyses of Cd concentrations and natural stable isotope compositions by multiple collector ICP-MS were conducted. Cadmium uptake and translocation decreased when Fe was removed from the hydroponic solutions, while the application of foliar Zn-EDTA may enhance Cd translocation. No significant differences in isotope fractionation during uptake were found between treatments. Data from all treatments fit a single Cd isotope fractionation model associated with sequestration (seq) of isotopically light Cd in roots and unidirectional mobilisation (mob) of isotopically heavier Cd to the leaves (ε114Cdseq-mob = -0.13‱). This result is in excellent agreement with data from an investigation of 19 genetically diverse cacao clones. The different Cd dynamics exhibited by the clones and seen in response to different Fe availability may be linked to similar physiological processes, such as the regulation of specific transporter proteins.

Assessment and Review of Heavy Metals Pollution in Sediments of the Mediterranean Sea

The impact of marine sediment pollution is crucial for the health of the seas, particularly in densely populated coastal areas worldwide. This study assesses the concentration and distribution of heavy metals in the marine sediments of the main regions of the Mediterranean Sea. The results underscore high concentrations of mercury (Hg), nickel (Ni), and copper (Cu), whereas chromium (Cr), zinc (Zn), cadmium (Cd), barium (Ba), and vanadium (V) exhibit moderate values. To assess the heavy metal results, sediment quality guidelines and pollution indices (Igeo and Geochemical Signal Type-GST) were employed, revealing a consistent trend of decreasing concentrations from the coastal zone to the open sea. Principal Component Analysis (PCA) emphasizes the significant roles of Cu, Zn, Ba, and Cr in sediment chemistry. The study suggests that the distribution patterns of heavy metals are linked to wastewater discharges in coastal areas, requiring effective management strategies to ensure the health of the Mediterranean Sea.

Placental cellular composition and umbilical cord tissue metal(loid) concentrations: A descriptive molecular epidemiology study leveraging DNA methylation

The placenta is a mixture of cell types, which may regulate maternal-fetal transfer of exogenous chemicals or become altered in response to exposures. We leveraged placental DNA methylation to characterize major constituent cell types and applied compositional data analysis to test associations with non-essential metal(loid)s measured in paired umbilical cord tissue (N = 158). Higher proportions of syncytiotrophoblasts were associated with lower arsenic, whereas higher proportions of Hofbauer cells were associated with higher cadmium concentrations in umbilical cords. These findings suggest that placental cellular composition influences amounts of metal(loid)s transferred to the fetus or that prenatal exposures alter the placental cellular makeup.

Synergistic Effects of Bicarbonate and Selenium on Cadmium Transport in Karst-Adaptable Plants Based on Plant Electrical Signals

High cadmium (Cd) concentrations associated with geochemical anomalies are prevalent in carbonate-rich karstic areas, posing serious ecological risks, while the karstic soils are rich in bicarbonate (HCO3−). It is known that Selenium (Se) is a mineral element that effectively mitigates the Cd transport in plant species. However, the synergistic effects of HCO3− and Se on Cd translocation in plant species have not yet been indicated. In this study, based on plant electrophysiological measurements, we chose Orychophragmus violaceus (Ov) as experimental material and determined the growth potential, water metabolism, and nutrient translocation capacity under HCO3−-Se6+-Cd2+ treatment to identify the synergistic effects of bicarbonate and selenium on cadmium transport in karst-adaptable plants. We found 5 mM HCO3− and 0.46 mM Se6+ synergistically alleviated the Cd2+ stress on Ov, promoting growth, intracellular water metabolism, nutrient translocation efficiency, and total Se accumulation, and inhibiting the uptake of Cd in Ov. Nevertheless, 15 mM HCO3− and 0.46 mM Se6+ synergistically augmented Cd transport on Ov, resulting in growth reduction, intracellular water metabolism, nutrient translocation efficiency, and total Se concentration. Hence, it not only provides a frontier approach for the real-time monitoring of intracellular water and nutrient utilization capacity in plant species, but is also even more a theoretical idea that reveals the synergistic effects of bicarbonate and selenium on cadmium transport of plants to precisely indicate selenium supplementation to ameliorate cadmium pollution and construct a sustainable karst ecosystem in the future.

Protecting the Achilles heel: three FolE_I-type GTP-cyclohydrolases needed for full growth of metal-resistant Cupriavidus metallidurans under a variety of conditions.

In Cupriavidus metallidurans and other bacteria, biosynthesis of the essential biochemical cofactor tetrahydrofolate (THF) initiates from guanosine triphosphate (GTP). This step is catalyzed by FolE_I-type GTP cyclohydrolases, which are either zinc-dependent FolE_IA-type or metal-promiscuous FolE_IB-type enzymes. As THF is also essential for GTP biosynthesis, GTP and THF synthesis form a cooperative cycle, which may be influenced by the cellular homeostasis of zinc and other metal cations. Metal-resistant C. metallidurans harbors one FolE_IA-type and two FolE_IB-type enzymes. All three proteins were produced in Escherichia coli. FolE_IA was indeed zinc dependent and the two FolE_IB enzymes metal-promiscuous GTP cyclohydrolases in vitro, the latter, for example, functioning with iron, manganese, or cobalt. Single and double mutants of C. metallidurans with deletions in the folE_I genes were constructed to analyze the contribution of the individual FolE_I-type enzymes under various conditions. FolE_IA was required in the presence of cadmium, hydrogen peroxide, metal chelators, and under general metal starvation conditions. FolE_IB1 was important when zinc uptake was impaired in cells without the zinc importer ZupT (ZIP family) and in the presence of trimethoprim, an inhibitor of THF biosynthesis. FolE_IB2 was needed under conditions of low zinc and cobalt but high magnesium availability. Together, these data demonstrate that C. metallidurans requires all three enzymes to allow efficient growth under a variety of conditions.IMPORTANCETetrahydrofolate (THF) is an important cofactor in microbial biochemistry. This "Achilles heel" of metabolism has been exploited by anti-metabolites and antibiotics such as sulfonamide and trimethoprim. Since THF is essential for the synthesis of guanosine triphosphate (GTP) and THF biosynthesis starts from GTP, synthesis of both compounds forms a cooperative cycle. The first step of THF synthesis by GTP cyclohydrolases (FolEs) is metal dependent and catalyzed by zinc- or metal-promiscuous enzymes, so that the cooperative THF and GTP synthesis cycle may be influenced by the homeostasis of several metal cations, especially that of zinc. The metal-resistant bacterium C. metallidurans needs three FolEs to grow in environments with both high and low zinc and cadmium content. Consequently, bacterial metal homeostasis is required to guarantee THF biosynthesis.

Limits to the adaptation of herbivorous spider mites to metal accumulation in homogeneous and heterogeneous environments.

Metal accumulation is used by some plants as a defence against herbivores. Yet, herbivores may adapt to these defences, becoming less susceptible. Moreover, ecosystems often contain plants that do and do not accumulate metals, but whether such heterogeneity affects herbivore adaptation remains understudied. Here, we performed experimental evolution to test whether the spider mite Tetranychus evansi adapts to plants with high cadmium concentrations, in homogeneous (plants with cadmium) or heterogeneous (plants with or without cadmium) environments. For that we used tomato plants, which accumulate cadmium, thus affecting the performance of these spider mites. We measured mite fecundity, hatching rate, and the number of adult offspring after 12 and 33 generations and habitat choice after 14 and 51 generations, detecting no trait change, which implies the absence of adaptation. We then tested whether this was due to a lack of genetic variation in the traits measured and, indeed, additive genetic variance was low. Interestingly, despite no signs of adaptation, we observed a decrease in fecundity and number of adult offspring produced on cadmium-free plants, in the populations evolving in environments with cadmium. Therefore, evolving in environments with cadmium reduces the growth rate of spider mite populations on non-accumulating plants. Possibly, other traits contributed to population persistence on plants with cadmium. This calls for more studies addressing herbivore adaptation to plant metal accumulation.

Dynamics of changes in cadmium levels in environmental objects and its impact on the bio-elemental composition of living organisms.

As a result of intensive anthropogenic impact in the biosphere there is a rapid process of accumulation of heavy metal salts. They have led to the aggravation of problems associated with the pollution of ecosystems and basic food products of plant and animal origin. Environmental pollution by these compounds is caused by their persistence in environmental objects, migration ability, accumulation by plants. This contributes to their accumulation in the human environment. A number of studies have shown that heavy metals have mutagenic, toxic effects and affect the intensity of biochemical processes. Therefore, the presence of heavy metals in the environment is extremely undesirable. Moreover, the ecological state of the environment is directly related to changes in the human internal environment. Deficiency or excess of certain bioelements in soils and drinking water or non-compliance with its stable chemical composition causes the development of dysmicroelementosis. The ecological situation of the Carpathian region is closely related to the state of soils and water resources. In this regard, it is advisable to study and control the level of cadmium compounds in the environment of the region. The study of the effect of cadmium intoxication on the macro- and microelement composition of the brain and myocardium of experimental animals is also worthwhile. Materials and methods. Soils and drinking water of the plain, foothill and mountainous zones of the region, as well as organs and tissues of experimental animals served as the object of research. Cadmium levels in drinking water and myocardial tissues and brain of experimental animals have been measured by atomic absorption spectroscopy. Results and discussion. The study of soils in the Prykarpattia region has revealed an increase in the toxic element cadmium. Its content is 1.1-1.5 times higher than background levels. The analysis of drinking water allowed to establish that a significant number of people living in the plain and foothill zone of the region consume water with a high content of cadmium. The main stages of cadmium intake and accumulation in plants have been analyzed. Significant disorders in the body of experimental animals under conditions of excessive intake of cadmium compounds have been revealed. It was accompanied by the accumulation of cadmium in the myocardium and brain, on the background of redistribution of vital macronutrients calcium and magnesium along with micronutrients copper and zinc. Thus, excessive intake of cadmium salts causes the development of dysmicroelementosis, which is accompanied by a violation of the homeostasis of a living organism. It is suggested to conduct continuous monitoring of the level of toxicants in the ecosystem as an integral component of environmental monitoring.

Effect of Cadmium Toxicity on Different Antioxidant Enzymes in Growing Wheat (Triticum aestivum L.) Seedlings

Assessing the impact of Cadmium (Cd) on plant cells requires an understanding of the defensive mechanisms and adaptive responses employed by plants to counteract the deleterious effects of Cd toxicity. Wheat seedlings were grown under different concentrations (0 µM, 100 µM and 500 µM) of Cadmium salt (CdCl2). The growth of metal-treated seedlings was significantly affected. This study evaluated the ecotoxicological effects of two experimental concentrations of Cadmium (100 µM and 500 µM) against water control. It has been examined in recent studies that the toxic effects of Cadmium comprising the variables in fresh weight, dry weight and germination percentage of the wheat seedlings, photosynthesis and enzymatic activities in different stresses after seven days of cadmium exposure on roots and shoots of wheat seedling. Different antioxidant enzyme activities such as catalase (CAT), ascorbic acid oxidase (AOX), catechol peroxidase (CPX), superoxide dismutase (SOD), acid and alkaline phosphatase and inorganic pyrophosphatase have been measured. The various enzyme activities were increased in roots treated with high concentrations (500 µM) of Cadmium but decreased at low concentrations (100 µM) with respect to water control. This result indicated a complex defense mechanism in the root tissues induced by Cadmium. This work provides valuable insights for future research on plant responses to heavy metal stress and advances our understanding of the complex relationship between Cd toxicity and the antioxidant defense system in wheat seedlings.

Гідроекологічна характеристика сучасного стану Запорізького (Дніпровського) водосховища та його приток

Purpose: to determine the hydroecological condition of the different areas of the Zaporizhzhia (Dnipro) reservoir and its tributaries (Samara River, Konoplyanka River), which are under technogenic pressure. Methodology: classical methods of determining hydrochemical indicators (pH, dissolved oxygen, carbon dioxide, permanganate oxidizability, anions and cations of organic and inorganic compounds) and microbiological parameters (total count of microorganisms and count of saprophytes) were used during the study. The content of heavy metals was determined by atomic absorption spectrophotometry. Findings: The study of the current hydroecological state of the Zaporizhzhia (Dnipro) reservoir in the summer period showed that, according to most parameters, the water quality did not exceed the MAC (maximum allowable concentration) for fish farming. The exception was the reduced oxygen dissolved concentration (by 10-25%) in almost all areas of the reservoir, and the high mineralization of water in the Samara Bay (2 MAC), due to the discharge of highly mineralized waters of the Samara River. In the long-term aspect, there is an increase in the total mineralization of the Samara River (4 MAC, which is under the influence of the discharge mine waters of the coal mining industry of Western Donbas. The analysis of the content of heavy metals in the reservoir indicated an increase in the concentration of copper - from 13 MAC in the Samara Bay to 21 MAC in the lower part of the reservoir. The Samara River was characterized by a high content of cadmium (1.5 MAC), copper (13 MAC), and nickel (2.3 MAC). Indicators of the ecological state of the Konoplyanka River had significant differences in its different areas: in the upper reaches of the river, where the economic and domestic effluents of the city of Kamianske and the tailings storage facilities for radioactive waste are located, water did not meet the MAC for oxygen content, carbon dioxide, nitrites, nitrates, mineral ions (Ca2+, Mg2+, Cl’, SO4-2), general mineralization and the count of saprophytic microorganisms; at the mouth of the river, exceeding the MAC for nitrate content and saprophytic microflora was recorded. Originality: data on the hydroecological state of the Zaporizhzhia (Dnipro) reservoir and its tributaries in the conditions of the war have been obtained. Practical value: the results of the conducted study can be used to develop a strategic program for the restoration of the ecosystem of the Dnipro reservoirs in the post-war period. Key words: Zaporizhzhia (Dnipro) reservoir, tributaries, hydrochemical parameters, count of microorganisms, heavy metals.

Effects of copper and cadmium on stream leaf decomposition: evidence from a microcosm study.

We seek to understand how copper and cadmium act on leaf litter decomposition by their effects on microbial conditioning and litter fragmentation by invertebrates. In this study, we evaluated, in an integrated manner, different biological elements responsible for functioning of streams. Thus, we performed a microcosm assay with different concentrations for the two metals and their combination, evaluating their effects on fungi sporulation rate, consumption rate by shredders, and, consequently, the leaf litter decomposition rates. Sporulation rates were affected by all copper concentrations tested 10 × = 16µg L-1 and 25 × = 40µg L-1) but significantly reduced only at the highest concentration of cadmium (25 × = 22.5µg L-1). Increased copper and cadmium concentrations reduced the consumption of leaf litter by Phylloicus at 60%. The concentrations (10 × and 25 ×) of both metals resulted in a reduction in decomposition rates. When combined, copper and cadmium negatively affected microbial conditioning, consumption by shredders, and leaf litter decomposition. Increases in concentrations of copper and cadmium directly affected organic matter decomposition in aquatic environments. Thus, the presence of a high concentration of heavy metals in aquatic environments alters the functioning of ecosystems. As trace-elements occur in a combined manner in environments, our results show that the combined effects of different metals potentiate the negative effects on ecosystem processes.